Production of Auxin Hormone by Fluorescent Pseudomonads

摘要

Plant growth promoting rhizobacteria (PGPR) are considered to promote plant growth directly or indirectly. Pseudomonas bacteria, specially P. fluorescens and P. putida are the most important kinds of PGPR. Production of auxin is one of the main reasons to promote yield because of inoculation with this bacteria.In this research fifty strains of Fluorescent pseudomonads belong to microbial bank of Soil and Water Research Institute,isolated from Iran soils,selected and evaluated about secretion of auxincompounds. In HPLC device, 72% of the strains exuded at least one type of indolic auxin composites. The amount of exuded IAA by P. fluorescens strains was varied from zero to 31.6 mg/1 while it was producing from zero to 24.08 mg/1 in P.putida. The amount of exuded IAM by P. fluorescens and P. putida was between 0-16.2 and 0-17.2 mg/1, respectively. Also these strains exuded 0-7.2 mg/1 ILA for P. fluorescens and 0-10 mg/1 for P.putida. Neither of experimented strains exuded the IBA. The results showedthat 65% of the studied P. fluorescens used IAM pathway to synthesize IAA and 35% used the IAM and IPyA path, while 48% of the P. putida through IAM, 41% through both pathes and 7% used the only IPyA path towards IAA synthesize. But 78% of the strains studied in spectrophotometery exuded auxins which their amounts were producing between 0-7.09 mg/1 for P. fluorescens and 0-4.40 mg/1 for P. putida strains.